[PATCH v8 08/10] vgaarb: Log bridge control messages when adding devices

From: Bjorn Helgaas
Date: Wed Jan 05 2022 - 19:07:53 EST


From: Huacai Chen <chenhuacai@xxxxxxxxxxx>

Previously vga_arb_device_init() iterated through all VGA devices and
indicated whether legacy VGA routing to each could be controlled by an
upstream bridge.

But we determine that information in vga_arbiter_add_pci_device(), which we
call for every device, so we can log it there without iterating through the
VGA devices again.

Note that we call vga_arbiter_check_bridge_sharing() before adding the
device to vga_list, so we have to handle the very first device separately.

Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/gpu/vga/vgaarb.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 455cf048fae8..b7e6c1228fff 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -719,8 +719,10 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)

vgadev->bridge_has_one_vga = true;

- if (list_empty(&vga_list))
+ if (list_empty(&vga_list)) {
+ vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
return;
+ }

/* okay iterate the new devices bridge hierarachy */
new_bus = vgadev->pdev->bus;
@@ -759,6 +761,11 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
}
new_bus = new_bus->parent;
}
+
+ if (vgadev->bridge_has_one_vga)
+ vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
+ else
+ vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n");
}

/*
@@ -1557,7 +1564,6 @@ static int __init vga_arb_device_init(void)
{
int rc;
struct pci_dev *pdev;
- struct vga_device *vgadev;

rc = misc_register(&vga_arb_device);
if (rc < 0)
@@ -1573,15 +1579,6 @@ static int __init vga_arb_device_init(void)
PCI_ANY_ID, pdev)) != NULL)
vga_arbiter_add_pci_device(pdev);

- list_for_each_entry(vgadev, &vga_list, list) {
- struct device *dev = &vgadev->pdev->dev;
-
- if (vgadev->bridge_has_one_vga)
- vgaarb_info(dev, "bridge control possible\n");
- else
- vgaarb_info(dev, "no bridge control possible\n");
- }
-
pr_info("loaded\n");
return rc;
}
--
2.25.1